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Re: openldap 2.4.16 hangs with dncachesize smaller than max number of records
- To: email@example.com
- Subject: Re: openldap 2.4.16 hangs with dncachesize smaller than max number of records
- From: Rodrigo Costa <firstname.lastname@example.org>
- Date: Wed, 17 Jun 2009 18:09:30 -0700 (PDT)
- Cc: email@example.com
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Maybe I'm not understanding very well your explanation.
What I can see is that until the dncache is filled any search can be
done very fast. After this is filled even stopping the original search
and starting a new one the pace is now very slow with some queries
taking around 8 seconds to end.
Once dncache is filled is there any configuration like cachefree that
could make the searches become similar to the original pace?
Howard Chu wrote:
> Rodrigo Costa wrote:
>> The idea was exactly to use the dncachesize large so the search or
>> random database access would not be affected.
>> The issue is that after DB is filled any search hangs time by time even
>> there are many entrances into cache. I was expecting that to remove or
>> re-cache an entrance some performance affectance would occur but if
>> ldapsearch would be stopped and a new one started the search would be
>> faster since there are millions of entrances already cached.
> Except that there *aren't* million of entries already cached, you've
> only cached a few thousand entries. And when you have such a tiny
> fraction of the database cached, the cache is going to be mostly
> useless for random access patterns. At this point you're making me
> repeat myself, so I'm stopping here.
> By the way, an "entrance" is a doorway. A directory object is an
> "entry" ...
> -- -- Howard Chu
> CTO, Symas Corp. http://www.symas.com
> Director, Highland Sun http://highlandsun.com/hyc/
> Chief Architect, OpenLDAP http://www.openldap.org/project/